Fluid storage container

ABSTRACT

A fluid storage container is provided including a cylindrical shell, a piston positioned within the cylindrical shell and vertically movable with respect thereto, a seal positioned between the periphery of the piston and the cylindrical shell in sealing engagement with the piston and the cylindrical shell to provide a fluid-tight storage area within a portion of the cylindrical shell, a fluid inlet in communication with the storage area for admitting fluid thereinto, and a counterweight mechanism connected to the piston for substantially counterbalancing the weight of the piston and for maintaining the piston centrally positioned within the cylindrical shell during vertical movement of the piston therewithin. The counterweight mechanism is connected to the piston through a focal point located vertically above and in vertical alignment with the center of the piston.

United States Patent 1191 Heisterberg [4 Sept. 10, 1974 [54] FLUID STORAGE CONTAINER FOREIGN PATENTS OR APPLICATIONS inventorr i g Heisietberg, Flossmoor, l06,097 12/1938 Australia 220/85 13 [73] Assignee: General American Transportation Examiner-William Price Corporation, Chicago, Ill.

Assistant Examiner-Stephen Marcus Attorney, Agent, or Firm-Prangley, Dithmar, Vogel,

[22] Filed: Feb. 16, 1972 Sandler & Stotland [21] Appl. No.: 226,897

[57] ABSTRACT 52 US. Cl 220/26 s, 73/321, 220/26 R A fluid Storage Container is Provided including a y 51 1111.01 B65d 87/18 drical shell, a Piston positioned within the cylindrical 53 Field f seal-din". 220 5 B, 5 A, 26 S 2 R, shell and vertically movable with respect thereto, a 220 2 1 2 1 73 32 52 3 66, seal positioned between the periphery of the piston 33, 121, 2 and the cylindrical shell in sealing engagement with the piston and the cylindrical shell to provide a fluid- 5 References Cited tight storage area within a portion of the cylindrical UNITED STATES PATENTS shell, a fluid in let in communication with the storage 8 753 12/1907 unyon 3/ x area hfor admltting flull therteinto, and fa courlijterweiglliit mec anism connecte to t e piston or su stantia y 220/26 57; counterbalancing the weight of the piston and for l:636:539 7/1927 Wiggins R maintaining the piston centrally positioned within the 2,050,686 8/1936 Wiggins 220/85 A ux cylindficaishell during vertical movement of the P 2,337,010 12/1943 Wiggins 220/3 5 3x ton therewithin. The counterweight mechanism is con- 2,408,539 10/ I946 Wiggins 220/26 R UX nected to the piston through a focal point located ver- 2,486,823 11/1949 Cranmer 220/26 R X tically above and in vertical alignment with the center 2,578,090 12/1951 Plummet 220/85 B of the pi ton 2,587,526 2/1952 Quist 73/321 2,677,816 5 1954 Quist 116/118 R x 13 Claims, 3 Drawing Figures PAIENIEU SEP 1 mm sum 1 or z I FIG. 1

PATENIED I 01914 308534.576

sum 2 or 2 FIG.2

FLUID STORAGE CONTAINER This invention is directed to an improved fluid storage container having a counterweighted piston therein, and more specifically to a fluid storage container wherein the counterweight mechanism is connected to the piston through a focal point located vertically above and in vertical alignment with the center of the piston.

It is an important object of the present invention to provide a fluid storage container including a cylindrical shell, a piston positioned within the cylindrical shell and vertically movable with respect thereto, a seal positioned between the periphery of the piston and the cylindrical shell in sealing engagement with the piston and the cylindrical shell to provide a fluid-tight storage area within a portion of the cylindrical shell, a fluid inlet in communication with the storage area for admitting fluid thereinto, and a counterweight mechanism connected to the piston for substantially counterbalancing the weight of the piston and for maintaining the piston centrally positioned within the cylindrical shell during vertical movement of the piston therewithin, the counterweight mechanism being connected to the piston through a focal point located vertically above and in vertical alignment with the center of the piston, whereby entrance of fluid into the storage area through the fluid inlet moves the piston vertically of the cylindrical shell.

Another object of the present invention is to provide a fluid storage container of the type set forth wherein the connection between the piston and the counterweight mechanism is three cables of equal length each being connected at one end thereof to the periphery of the piston at equidistant intervals from the other of the cables.

A further object of the present invention is to provide a fluid storage container of the type set forth wherein the counterweight mechanism is housed within and guided by a guide positioned on the outside of the storage container to provide an indication of the amount of fluid stored therewithin.

The invention, both as to its organization and method of operation, together with further objects and advantages thereof, will best be understood by reference to the following specification taken in connection with the accompanying drawings in which:

FIG. 1 is a side-sectional view of the fluid storage container embodying the present invention with portions thereof shown in elevation; 7

FIG. 2 is a sectional view of the fluid storage container shown in FIG. 1 taken along lines 22 thereof; and

FIG. 3 is an enlarged elevational view of the sheaves employed with the present invention.

Referring now to the drawings, there is disclosed a fluid storage tank 100-including a cylindrical side wall 101 being closed at the bottom end thereof by a bottom wall 102 and closed at the top thereof by a conically or dome shaped top wall 103. The top wall 103 is provided with a housing 105 including an upstanding side wall 106 integral with the conical top wall 103. The side wall 106 of the housing 105 has an aperture 107 therein and is closed at the top thereof by a roof structure 108.

The side wall 101 of the fluid storage tank 100 is provided with spaced-apart side vents l 12 and l 13, as seen in the left-hand portion of FIG. 1, which vents 112 and 113 provide communication between the atmosphere and the inside of the storage tank 100. The fluid storage tank is further provided with an aperture 115 near the bottom wall 102, which aperture 115 receives therein a condensate drain pipe 120, the condensate drain pipe being provided with a valve (not shown) so as to maintain the fluid-tight integrity of the fluid storage tank 100.

The fluid storage tank 100, and particularly the side wall 101 thereof, is further provided with an aperture near the bottom wall 102, which aperture is connected by means of a collar 126 to an inlet-outlet pipe 130. The collar 126 provides a fluid-tight connection between the fluid storage tank 100 and the inlet-outlet pipe 130, which pipe 130 is provided with an upstanding stack 131 having a vent structure 132 at the top thereof connected to the stack 131 at a flange 133 provided with the usual rivets. The vent structure 132 is normally closed but will open if a predetermined pressure in the tank 100 is exceeded.

The fluid storage tank 100 is further provided with a piston 135 housed within the side wall 101 of the tank 100. The piston 135 is formed of a conical or dome shaped sheet 136 having an apex 137. The periphery of the piston 135 is provided with an upstanding flange 140 which is provided at the distal end thereof with an inturned flange 141. The piston 135, the upstanding flange 140 and the inturned flange 141' may be formed of an integral piece of material.

A seal 145 is provided in the form of a cylindrical section, which seal 145 is flexible and impervious to the fluid to be stored. The seal 145 is provided with an end 146 which is securely fastened between the inturned flange 141 and a circular flange 150 coterminous with the flange 141 and securely fastened thereto by means of fasteners 151 extending 7 through the flanges at spaced apart intervals circumferentially around the flanges. The seal 145 has the other end 147 thereof securely fastened between flanges 155 and 156, which flanges 155 and 156 are securely connected to the side wall 101 of the fluid storage tank 100 and extend circumferentially therearound. It is seen, therefore, that the seal 145 is sealingly connected at one end-thereof to the piston 135 and at the other end thereof to the side wall 101 of the fluid storage tank 100.

A counterweight mechanism 160 includes a counterweight slidably positioned'within a guide 1 70. The guide includes a front wall 171, a back wall 172 and side walls 173 interconnecting the front wall-and the back wall. The back wall 172 is fixedly connected to the side wall 101 of the fluid storage tank 100, such as by welding. The front wall 171 of the guide 170 is provided with an elongated slot 175 which receives therein a level indicator 176 fixedly connected to the counterweight 165. A

There is further provided three cables 180 of the same length, each of the cables 180 being connected at one end thereof to the counterweight 165. A triple sheave is rotatably mounted'on an axle 186 supported between two mounting plates 187, the mounting plates 187 being positioned on the top wall 103 of the fluid storage tank 100 near the side wall 101 so'as to provide a substantially vertical path for the cables 180 passing over the sheave 185 to the counterweight 165. Another triple sheave 190 is positioned within the housing 105 and mounted for rotation about an axle 191 fixedly mounted to the side wall 106 of the housing 105. The sheave 190 is positioned so that the initial point of contact between the cables 180 and the sheave 190 is located vertically above and in vertical alignment with the center of the piston 135 as denoted by the apex 137. Slightly below the sheave 190 are positioned three individual single sheaves 195, each being mounted for rotation about an axle 196, which axle 196 is fixedly mounted to the housing 105. Each of the sheaves 195 is angularly placed so as to guide the associated one of the cables 180 in its path from the sheave 190 to a gusset plate 200 fixedly connected to the pe riphery of the piston 135 and provided with an aperture 201 to receive therein the associated cable 180. The gusset plates 200 are angularly separated by 120 so as to provide three points of support for the piston 135, each of the points of support being equidistant from the other two points of support.

Each of the cables 180 extends from the respective gusset plate 200 upwardly to the associated single sheave 195 and thereafter to the triple sheave 190 out of the housing 105 through the aperture 107-to the sheave 185 and finally to the counterweight 165. The counterweight 165 is of sufficient mass substantially to offset the weight of the piston 135 so that fluid entering the inlet-outlet pipe 130 will move the piston 135 vertically upwardly in the tank 100 with a corresponding downward movement of the counterweight 165, the level indicator 176 moving therewith in the slot 175 to provide an indication of the amount of fluid within the tank 100.

Operation of the fluid storage tank 100 will now be explained. Referring now to FIG. 1 of the drawings, the piston 135 is shown in full line at the bottom of the fluid storage tank 100 wherein the piston 135 and particularly the edges of the piston 135 are in contact with the bottom wall 102 of the tank 100. In this position there is substantially no fluid in the area between the seal 145 and the adjacent wall 101, which area is a fluid-tight area due to the presence of the seals 155 and 156 sealing the end 147 of the seal 145 to the side wall 101 and the presence of the flanges 150 and 141 sealing the other end 146 of the seal 145 therebetween. As fluid enters the inlet-outlet pipe 130, the piston is forced upwardly to the phantom line position thereof shown in FIG. 1 with the seal 145 also being in the phantom line position there illustrated. Movement of the piston 135 from the full line position thereof to the phantom line position thereof is assisted by the vents 112 and 113 which facilitate escape of air from the storage tank 100 above the piston 135. After the piston 135 has reached the phantom line position thereof, additional fluid introduced through the inlet-outlet pipe 130 will vent through the stack 131.

The level of the piston 135 within the tank 100 is easily determined by the position of the level indicator 176 which is attached to the counterweight 165 and moves therewith. lndicia (not shown) provided on the front wall 171 of the guide 170 serves to indicate the position of the piston 135 within the tank 100.

Since, as seen in FIGS. 1 and 2, each of the cables 180 is gathered at an area substantially in vertical alignment with the center of the piston 135, as by the single sheaves 195, the piston 13S moves from its full line position in FIG. 1 to its phantom line position therein without undue tilting thereof or movement from the center of the tank 100. Since the present arrangement of the cables 180 provides both the raising and centering function for the piston 135, internal structure for centering the piston is not needed thereby increasing the useful storage area of the tank to about 85% of the total volume of the tank 100. As may be seen, the sum of the vector forces on each of the cables 180 is equal to one-third of the counterweight 165 when the piston is in equilibrium. Since the force on any one of the cables 180 may range from one-third the weight of the counterweight to the entire weight of the counterweight 165, there is provided sufficient force within the system for maintaining the piston 135 in the proper attitude as it moves vertically of the tank 100. Due to the combination of sheaves 185, 190 and 195 and the positioning of the attachment points of the cables to the piston 135, there is disclosed a selfregulating mechanism for maintaining the piston 135 in the proper attitude as well as centrally located of the tank 100 as the piston moves vertically therewithin. Because one function of the sheaves 195 is to position the cables 180 below the sheave so that the cables 180 initially contact the sheave 190 in vertical alignment with the center of the piston 135, alternative structure which accomplishes the same purpose may be substituted therefor.

The fluid storage tank of the present invention is particularly adaptable to handle petrochemical or petroleum vapors generated as a result of evaporation in liquid storage tanks or through liquid transfer operations. The fluid storage container 100 is particularly suitable for storing the vapor prior to the recondensation thereof, which storage also prevents environmental pollution. While the fluid storage container of the present invention is primarily intended to store vapors, condensation of some of the vapors may occur due to change in temperature or pressure within the tank 100. To that end, there is provided the condensate outlet 120 which may be used to remove any of the condensed vapors in the tank. One or more limit switches (not shown) may be activated by the counterweight 165 automatically to effect withdrawal of vapors stored in the tank 100 when the piston 13S reaches a predetermined position.

The seal 145 may be made of any art recognized material, such as Buna-N rubber or various cloth materials coated with a suitable synthetic organic resin, such as a nylon or polyester cloth coated at least on one side with a natural or synthetic rubber or a polyvinyl chloride synthetic organic resin. The important properties of the seal 145 are that it be impervious to the fluid being stored and that it be flexible so as to move between the full line position and the phantom line position thereof shown in FIG. 1 without cracking and that it be chemically inert to the fluid being stored. The tank 100 and piston 135 may be made of any suitable metal,

such as steel, resistant to corrosion and chemically inert with respect to the vapors being stored therein.

While there has been described what is at present considered to be the preferred embodiment of the invention, it will be understood that various modifications may be made therein and it is intended to cover in the appended claims all such modifications as fall within the true spirit and scope of the invention.

What is claimed is: l. A fluid storage container including a cylindrical shell, a piston positioned within said cylindrical shell and vertically movable with respect thereto, a seal positioned between the periphery of said piston and said cylindrical shell in sealing engagement with said piston and said cylindrical shell to provide a fluid-tight storage area within a portion of said cylindrical shell, a fluid inlet in communication with said storage area for admitting fluid thereinto, and a counterweight mechanism connected to said piston for substantially counterbalancing the weight of said piston and for maintaining said piston centrally positioned within said cylindrical shell during vertical movement of said piston therewithin, said counterweight mechanism being connected to said piston by at least three flexible cables of equal length each connected at one end thereof to the periphery of said piston at equidistant intervals from the others of said flexible cables and extending through a vertically fixed member located vertically above and in vertical alignment with the center of said piston, whereby entrance of fluid into said storage area through said fliud inlet moves said piston vertically of said cylindrical shell.

2. The fluid storage container set forth in claim 1, wherein said piston is a conically shaped metal sheet with the apex of the cone in vertical alignment with the focal point.

3. The fluid storage container set forth in claim 1, wherein said piston is shaped so as to provide a fluid storage volume of about 85% of the gross volume of said storage container.

4. The fluid storage container set forth in claim 1, wherein said counterweight mechanism is connected to said piston by three cables.

5. The fluid storage container set forth in claim 1, wherein said piston has at the periphery thereof an upstanding flange integral with an intumed flange to provide support for one end of said seal.

6. The fluid storage container set forth in claim 1, wherein said piston is provided with at least three gusset plates for connecting the one ends of said cables to said piston.

7. The fluid storage container set forth in claim 1, wherein said counterweight mechanism includes a single counterweight positioned outside of said storage container and connected to each of said cables.

8. The fluid storage container set forth in claim 1, and further including mechanism positioned intermediate said focal point and said piston for restricting the movement of said cables to prevent tipping and tilting and off center movement of said piston during movement thereof vertically of said cylindrical shell.

9. A fluid storage tank including a cylindrical shell having guide structure on the outside of said shell extending a predetermined vertical distance therealong, a piston positioned within said cylindrical shell and vertically movable with respect thereto, a seal positioned between the periphery of said piston and said cylindrical shell in sealing engagement with said piston and said cylindrical shell to provide a fluid-tight storage area within a portion of said cylindrical shell, a fluid inlet in communication with said storage area for admitting fluid thereinto, and a counterweight connected to said piston for substantially counterbalancing the weight of said piston and for maintaining said piston centrally positioned within said cylindrical shell during vertical movement of said piston therewithin, said counterweight being connected to said piston by three flexible cables of equal length each connected at one end thereof to the periphery of said piston at equidistant intervals from the others of said cables and extending through a vertically fixed member located vertically above and in vertical alignment with the center of said piston, said counterweight slidably fitting within said guide mechanism and sliding therealong corresponding to different positions of said piston within said cylindrical shell, the position of said counterweight in said guide mechanism providing information relative to the amount of fluid within said shell, whereby entrance of fluid into said storage area through said fluid inlet moves said piston vertically of said cylindrical shell.

10. The fluid storage container set forth in claim 9, wherein said guide structure is an elongated rectangular housing having internal dimensions slightly greater than the external dimensions of said counterweight, thereby to restrict lateral movement of said counterweight during vertical movement with respect to said fluid storage container.

11. The fluid storage container set forth in claim 9, wherein said guide structure has a slot in one side thereof for receiving therethrough a level indicator positioned on said counterweight, thereby to provide information as to the level of fluid inside said fluid storage tank.

12. A fluid storage container including a cylindrical shell, a piston positioned within said cylindrical shelland vertically movable with respect thereto, a seal positioned between the periphery of said piston and said cylindrical shell in sealing engagement with said piston and said cylindrical shell to provide a fluid-tight storage area within a portion of said cylindrical shell, a fluid inlet in communication with said storage area for admitting fluid thereinto, a counterweight mechanism connected to said piston for substantially counterbalancing the weight of said'piston and for maintaining said piston centrally positioned within said cylindrical shell during vertical movement of said piston therewithin, at least a three cable sheave positioned vertically above the center of said piston, and at least three cables of equal length each connected at one end thereof to the periphery of said piston at equidistant intervals from the others of said cables extending upwardly through a focal point located vertically above and in vertical alignment with the center of said piston to contact said sheave and over said sheave to said counterweight mechanism, whereby entrance of fluid into said storage area through said fluid inlet moves said piston vertically of said cylindrical shell.

13. A fluid storage container including a cylindrical shell, a piston positioned within said cylindrical shell and vertically movable with respect thereto, a seal positioned between the periphery of said piston and said cylindrical shell in sealing engagement with said piston and said cylindrical shell to provide a fluid-tight storage area within a portion of said cylindrical shell, a fluid inlet in communication with said storage area for admitting fluid thereinto, a counterweight mechanism connected to said piston for substantially counterbalancing the weight of said piston and for maintaining said piston centrally positionedwithin said cylindrical shell during vertical movement of said piston therewithin, said counterweight mechanism being connected to said piston by at least three cables of equal length each connected at one end thereof to the periphery of said piston at equidistant intervals from the others of said cables and extending through a focal point located vertically above and in vertical alignment with the cen- 3,834,576 7 8 ter of said piston, each of said cables passing over a said cylindrical shell, whereby entrance of fluid into sheave intermediate the focal and said said storage area through said fluid inlet moves said pispiston for restricting movement of the associated cable to prevent tipping and tilting and off-center movement of said piston during movement thereof vertically of ton vertically of said cylindrical shell. 

1. A fluid storage container including a cylindrical shell, a piston positioned within said cylindrical shell and vertically movable with respect thereto, a seal positioned between the periphery of said piston and said cylindrical shell in sealing engagement with said piston and said cylindrical shell to provide a fluid-tight storage area within a portion of said cylindrical shell, a fluid inlet in communication with said storage area for admitting fluid thereinto, and a counterweight mechanism connected to said piston for substantially counterbalancing the weight of saId piston and for maintaining said piston centrally positioned within said cylindrical shell during vertical movement of said piston therewithin, said counterweight mechanism being connected to said piston by at least three flexible cables of equal length each connected at one end thereof to the periphery of said piston at equidistant intervals from the others of said flexible cables and extending through a vertically fixed member located vertically above and in vertical alignment with the center of said piston, whereby entrance of fluid into said storage area through said fliud inlet moves said piston vertically of said cylindrical shell.
 2. The fluid storage container set forth in claim 1, wherein said piston is a conically shaped metal sheet with the apex of the cone in vertical alignment with the focal point.
 3. The fluid storage container set forth in claim 1, wherein said piston is shaped so as to provide a fluid storage volume of about 85% of the gross volume of said storage container.
 4. The fluid storage container set forth in claim 1, wherein said counterweight mechanism is connected to said piston by three cables.
 5. The fluid storage container set forth in claim 1, wherein said piston has at the periphery thereof an upstanding flange integral with an inturned flange to provide support for one end of said seal.
 6. The fluid storage container set forth in claim 1, wherein said piston is provided with at least three gusset plates for connecting the one ends of said cables to said piston.
 7. The fluid storage container set forth in claim 1, wherein said counterweight mechanism includes a single counterweight positioned outside of said storage container and connected to each of said cables.
 8. The fluid storage container set forth in claim 1, and further including mechanism positioned intermediate said focal point and said piston for restricting the movement of said cables to prevent tipping and tilting and off center movement of said piston during movement thereof vertically of said cylindrical shell.
 9. A fluid storage tank including a cylindrical shell having guide structure on the outside of said shell extending a predetermined vertical distance therealong, a piston positioned within said cylindrical shell and vertically movable with respect thereto, a seal positioned between the periphery of said piston and said cylindrical shell in sealing engagement with said piston and said cylindrical shell to provide a fluid-tight storage area within a portion of said cylindrical shell, a fluid inlet in communication with said storage area for admitting fluid thereinto, and a counterweight connected to said piston for substantially counterbalancing the weight of said piston and for maintaining said piston centrally positioned within said cylindrical shell during vertical movement of said piston therewithin, said counterweight being connected to said piston by three flexible cables of equal length each connected at one end thereof to the periphery of said piston at equidistant intervals from the others of said cables and extending through a vertically fixed member located vertically above and in vertical alignment with the center of said piston, said counterweight slidably fitting within said guide mechanism and sliding therealong corresponding to different positions of said piston within said cylindrical shell, the position of said counterweight in said guide mechanism providing information relative to the amount of fluid within said shell, whereby entrance of fluid into said storage area through said fluid inlet moves said piston vertically of said cylindrical shell.
 10. The fluid storage container set forth in claim 9, wherein said guide structure is an elongated rectangular housing having internal dimensions slightly greater than the external dimensions of said counterweight, thereby to restrict lateral movement of said counterweight during vertical movement with respect to said fluid storage container.
 11. The fluiD storage container set forth in claim 9, wherein said guide structure has a slot in one side thereof for receiving therethrough a level indicator positioned on said counterweight, thereby to provide information as to the level of fluid inside said fluid storage tank.
 12. A fluid storage container including a cylindrical shell, a piston positioned within said cylindrical shell and vertically movable with respect thereto, a seal positioned between the periphery of said piston and said cylindrical shell in sealing engagement with said piston and said cylindrical shell to provide a fluid-tight storage area within a portion of said cylindrical shell, a fluid inlet in communication with said storage area for admitting fluid thereinto, a counterweight mechanism connected to said piston for substantially counterbalancing the weight of said piston and for maintaining said piston centrally positioned within said cylindrical shell during vertical movement of said piston therewithin, at least a three cable sheave positioned vertically above the center of said piston, and at least three cables of equal length each connected at one end thereof to the periphery of said piston at equidistant intervals from the others of said cables extending upwardly through a focal point located vertically above and in vertical alignment with the center of said piston to contact said sheave and over said sheave to said counterweight mechanism, whereby entrance of fluid into said storage area through said fluid inlet moves said piston vertically of said cylindrical shell.
 13. A fluid storage container including a cylindrical shell, a piston positioned within said cylindrical shell and vertically movable with respect thereto, a seal positioned between the periphery of said piston and said cylindrical shell in sealing engagement with said piston and said cylindrical shell to provide a fluid-tight storage area within a portion of said cylindrical shell, a fluid inlet in communication with said storage area for admitting fluid thereinto, a counterweight mechanism connected to said piston for substantially counterbalancing the weight of said piston and for maintaining said piston centrally positioned within said cylindrical shell during vertical movement of said piston therewithin, said counterweight mechanism being connected to said piston by at least three cables of equal length each connected at one end thereof to the periphery of said piston at equidistant intervals from the others of said cables and extending through a focal point located vertically above and in vertical alignment with the center of said piston, each of said cables passing over a sheave positioned intermediate the focal point and said piston for restricting movement of the associated cable to prevent tipping and tilting and off-center movement of said piston during movement thereof vertically of said cylindrical shell, whereby entrance of fluid into said storage area through said fluid inlet moves said piston vertically of said cylindrical shell. 